Hi there me and my brother in-law went to Rona and got them to cut some 3/4 mdf for us for my 2 13w3v3's and we are using these dimensions 35" Width, 17" Height, 20 1/4" Depth, Cubic Feet. 5.72 (2.86 Per Sub) from a box that hifi sound connection on ebay uses and was wondering what the dimensions of the port would be and it will be in the center with the subs sharing the air space.

Here is a link to the box style we are using. JL 13w3 box

Also JL specs say for the 4ohm tune to 27 and f3 is 35.

Thanks

 

If you build it with a 2.5" wide and 17" port you will wind up with an internal volume of 5.145 ft^3 after port displacement.